Die and die device

ABSTRACT

A die body includes a die hole for punching a work. A core, including a discharge hole, which is in communication with the die hole, is provided in the die body. The core is provided with a plurality of fluid injection ports through which fluid is injected downward of the discharge hole. The die body is provided with inflow ports through which compressed fluid flows into the fluid injection ports. The core is made of resin. The discharge hole is tapered toward its upper side. An outer peripheral surface of the die body is provided with a peripheral groove which is in communication with the inflow ports.

TECHNICAL FIELD

The present invention relates to a die and a die apparatus used forpunch press, and more particularly, to a die and a die apparatus whichcan prevent a punching, such as a blank and a scrap punched out from awork by a punch and a die, from rising together with the punch (slugrising).

BACKGROUND ART

In a conventional punch press, when a plate-like work is punched outusing a punch and a die, it is known that a punching rises together withthe punch (slug rising) when the punch rises. In a state where thepunching rises to an upper surface of a work, if a punching working oroperation of a next work is carried out successively, the punchingoperation of the work may be carried out while the punching isinterposed between the works in some cases, and the punch may bedamaged.

In order to prevent the punching from rising, a die hole of the die iscontrived variously, or the punching is drawn from below the die. Forexample, Japanese Utility Model Application Publication No. S52-50475discloses a technique for drawing the punching downward.

In a first conventional technique, a die is mounted on an upper surfaceof a die holder, the die holder is provided with a discharge holethrough which a punching punched out by the die is dropped, and an airhole from which air is injected is inclined and provided in thedischarge hole such that the air hole is directed downward. Air isinjected downwardly from the air hole into the discharge hole, therebysucking air from above the discharge hole.

In this structure, there are problems that it is difficult to form theair hole, a distance from the air hole to the die hole of the die islong, and the sucking effect is not sufficient.

Other than the first conventional technique, there are second and thirdconventional techniques disclosed in Japanese Patent Publication No.3245935 and Japanese Patent Application Laid-Open No. Hei-5-57687.

In structures of the second and the third conventional techniques, anair injection hole is inclined from a peripheral surface of acylindrical die to a discharge hole. If the air injection hole isexpressed in a sectional view of an end surface taken along an axis ofthe die at an outer peripheral surface of the die, the air injectionhole is worked from a portion expressed as a straight line which is inparallel to the axis of the die. Therefore, the conventional techniquehas a problem that it is troublesome to work the air injection hole, andthe structure becomes expensive. When the air injection hole is deep,there are problems that a thin and long drill is required, and when theworking of the air injection hole is started, a tip end of the drill isprone to deviate from the working position, the drill is prone to bebent and damaged.

The present invention has been achieved in order to solve the aboveproblems, and it is an object of the present invention to provide a dieand a die apparatus that can prevent a punching from rising.

DISCLOSURE OF THE INVENTION

To achieve the above object, a first aspect of the present inventionprovides a die, comprising: a die body having a die hole for punching awork; and a core provided in the die body and having a discharge holewhich is in communication with the die hole, wherein the core isprovided with a plurality of fluid injection ports for obliquelyinjecting fluid downward of the discharge hole, and the die body isprovided with an inflow port through which compressed fluid flows intothe fluid injection port.

A second aspect of the present invention provides the die according tothe first aspect, wherein the core is made of resin, and the dischargehole is tapered toward its upper side.

A third aspect of the present invention provides the die according tothe first or the second aspect, wherein an outer peripheral surface ofthe die body is formed with a peripheral groove which is incommunication with the inflow port.

A fourth aspect of the present invention provides a die apparatus,comprising: a die body having a die hole for punching a work; and a dieholder formed with a die mounting hole for detachably holding the diebody, wherein the die body is provided with a negative pressuregenerator which downwardly draws a punching punched out by the die hole,the die body is provided with an inflow port through which compressedfluid flows into the negative pressure generator, and the die holder isprovided with a fluid supply hole through which the compressed fluid issupplied to the inflow port.

A fifth aspect of the present invention provides the die apparatusaccording to the fourth aspect, wherein the die mounting hole isprovided at its upper portion and lower portion with a seal sectionwhich prevents the compressed fluid from leaking.

According to the die of the first to the third aspects, and the dieapparatus of the fourth and the fifth aspects, since the resin core isfitted into the recess of the die, the die can be reduced in weight.

A negative pressure generator which draws and drops the punching punchedout by the die hole of the die can be formed near the die hole, and theabove conventional problems can be overcome.

A sixth aspect of the present invention provides a die, comprising: adie body provided at its upper portion with a die hole; a discharge holeformed in the die body and having a diameter larger than that of the diehole; and a hole-forming tool engaging section formed on an outerperipheral surface of the die body, wherein the hole-forming toolengaging section is formed with an inclined air injection hole forinjecting air downward of the discharge hole.

A seventh aspect of the present invention provides the die according tothe sixth aspect, wherein the hole-forming tool engaging section is aportion of a peripheral groove formed in an outer peripheral surface ofthe die body.

An eighth aspect of the present invention provides the die according tothe sixth or the seventh aspect, wherein the hole-forming tool engagingsection is an inclined surface formed on an outer peripheral surface ofthe die body by countersinking working.

A ninth aspect of the present invention provides a die, comprising: adie body provided at its upper portion with a die hole; and a dischargehole formed in the die body and having a diameter larger than that ofthe die hole, wherein the die body is formed with a through hole whichis in communication with the discharge hole and an outer piece is fittedinto the through hole, and the outer piece is formed with an inclinedair injection hole for injecting air downward of the discharge hole.

A tenth aspect of the present invention provides a die, comprising: adie body provided at its upper portion with a die hole; and a dischargehole formed in the die body and having a diameter larger than that ofthe die hole, wherein an inner peripheral surface of the die body isprovided with a hole-forming tool engaging section, and the hole-formingtool engaging section is formed with an inclined air injection hole forinjecting air downward of the discharge hole.

An eleventh aspect of the present invention provides the die accordingto the tenth aspect, wherein the hole-forming tool engaging section is aportion of an inner peripheral groove formed in an inner peripheralsurface of the die body, or a countersunk portion, or a tapered surface.

A twelfth aspect of the present invention provides the die according tothe tenth or the eleventh aspect, wherein the air injection hole isconnected to a communication hole formed from an outer peripheralsurface of the die body.

According to the die of the sixth to the twelfth aspects, the airinjection hole which is inclined with respect to the die body of the diecan easily be formed, and the above conventional problems can beovercome.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view for explaining a die and a die apparatusaccording to an embodiment of the present invention;

FIG. 2 is an explanatory view showing a second embodiment of the dieaccording to the present invention;

FIG. 3 is an explanatory view showing a third embodiment of the dieaccording to the present invention;

FIGS. 4A and 4B are explanatory views showing a fourth embodiment of thedie according to the present invention;

FIGS. 5A and 5B are explanatory views showing a fifth embodiment of thedie according to the present invention;

FIGS. 6A and 6B are explanatory views showing a sixth embodiment of thedie according to the present invention;

FIGS. 7A and 7B are explanatory views of an outer piece according to thepresent invention;

FIGS. 8A, 8B, and 8C are explanatory views showing a seventh embodimentof the die according to the present invention;

FIGS. 9A and 9B are explanatory views showing an eighth embodiment ofthe die according to the present invention;

FIG. 10 is an explanatory view showing a ninth embodiment of the dieaccording to the present invention;

FIG. 11 is an explanatory view showing a tenth embodiment of the dieaccording to the present invention;

FIG. 12 is an explanatory view showing a partial modification of thetenth embodiment of the die according to the present invention;

FIG. 13 is an explanatory view showing another partial modification ofthe tenth embodiment of the die according to the present invention; and

FIG. 14 is a bottom view of a die holder of an eleventh embodiment of adie apparatus according to the present invention.

THE BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be explained in detail withreference to the accompanying drawings.

With reference to FIG. 1, a die apparatus 1 of an embodiment of thepresent invention includes a die base 3 mounted on an appropriate punchpress (not shown) such as a turret punch press. A die holder 7 having aplurality of detachable dies 5 is detachably mounted on the die base 3.

Each of the dies 5 includes a die body 11 which is provided at its upperportion with a die hole 9 to punch out a plate-like work together with apunch (not shown). A core 15 includes, in the die body 11, a dischargehole 13 which is in communication with the die hole 9. That is, alarge-diameter recess 17 which is in communication with the die hole 9is formed in the die body 11, and the core 15 is fitted into the recess17.

The core 15 is made of appropriate resin. A convex stripe 21 is providedon an outer peripheral surface of a lower portion of the core 15, theconvex stripe 21 being engaged with a peripheral groove 19 formed in aninner peripheral surface of a lower portion of the recess 17 so that thecore 15 does not easily come out from the recess 17. An outer peripheralsurface of an upper portion of the core 15 is formed with a peripheralgroove 23 which is in communication with a plurality of fluid injectionports 25.

The fluid injection ports 25 are provided in a circumferential directionof the discharge hole 13 at equal distances from one another, and thefluid injection ports 25 are inclined such that compressed air isinjected downward of the discharge hole 13. The die body 11 is providedwith a plurality of inflow ports 27 from which the compressed air flowsinto the fluid injection ports 25. Peripheral grooves 29 which are incommunication with the inflow ports 27 are formed in an outer peripheralsurface of the die body 11. The fluid injection port 25 may injectcompressed air in a direction deviated from an axis of the dischargehole 13 in a radial direction such that the compressed air injected fromthe fluid injection port 25 causes a rotational flow in the dischargehole 13.

In the die apparatus 1, the die holder 7 includes die mounting holes 31into which the dies 5 are detachably fitted. Each die holder 7 isprovided with a fluid supply hole 35 which is in communication with acompressed air supply hole 33 formed in the die base 3. The fluid supplyhole 35 is in communication with the die mounting holes 31 at positionscorresponding to the peripheral grooves 29 of the dies 5 mounted in thedie mounting holes 31. It is desirable that an O-ring 37 as a sealsection is provided between an upper portion and a lower portion of eachdie mounting hole 31 to prevent the compressed air from leaking from agap between an inner peripheral surface of the die mounting hole 31 andan outer peripheral surface of the die body 11.

In the above structure, the compressed air supply hole 33 provided inthe die base 3 is connected to a pressure source (not shown) such as acompressor, and if compressed air is supplied to the fluid supply hole35, the compressed air flows in from the inflow ports 27 of the die body11, and the compressed air is injected from the fluid injection port 25downward of the discharge hole 13.

Therefore, the compressed air injected from the fluid injection port 25downward of the discharge hole 13 forms a downward air flow and withthis, outside air is drawn from the die hole 9. That is, a negativepressure is generated in the underside close to the die hole 9. Aplate-like work is positioned on the die 5 and if the work is punchedout using the punch (not shown) and the die 5, the punching such as ablank or a scrap punched out into the die hole 9 is drawn downward, andis discharged out from the discharge hole 3H of the die base 3.Therefore, when the punch is moved upward, the punching is preventedfrom rising (slug rising).

As already understood, according to the present embodiment, the fluidinjection port 25 which injects compressed air downward in the dischargehole 13 is provided in the die 5, the compressed air is injected fromthe fluid injection port 25 and the air flow is generated to create thenegative pressure, and the negative pressure draws the outside air. Thisportion comes close to the die hole 9 of the die 5, and the drawingoperation from the die hole 9 into the downward direction of thepunching can effectively be carried out.

The outer peripheral surface of the die body 11 is provided with theperipheral groove 29 which is in communication with the inflow ports 27.Therefore, the compressed air can be supplied to the inflow ports 27equally. Since the resin core 15 is provided in the recess 17 of the diebody 11, the die 5 can be reduced in weight. Since the core 15 is madeof resin, the inclined fluid injection port 25 and the like can beformed easily.

Since the seal section is provided on the upper portion and the lowerportion of the die mounting hole 31 of the die holder 7, the compressedair can be prevented from leaking from the die mounting hole 31, and thepressure of the compressed air can be prevented from lowering.

Since the dies 5 are independently used and are not used simultaneously,it is desirable that the die mounting holes 31 and the fluid supplyholes 35 are independently connected to each other through switch valves(not shown), and compressed air is independently supplied to the diemounting holes 31 in correspondence with the dies 5 to be used. However,when the capacity of the pressure source is great and there is noproblem in supplying the compressed air to the plurality of die mountingholes 31 simultaneously, the compressed air may be supplied to theplurality of die mounting holes 31 at the same time.

The diameter of the inclined fluid injection port 25 may be set smallerthan that of the inflow port 27 or may be set equal thereto. If thediameter of the inclined fluid injection port 25 is set smaller thanthat of the inflow port 27, the flow rate of the compressed air in thefluid injection port 25 is increased, the drawing operation of thecompressed air from the die hole 9 into the downward direction of thepunching can be carried out more effectively.

FIG. 2 shows a second embodiment of the die 5. In the second embodiment,a resin core 39 which is tightly fitted into the recess 17 of the diebody 11 is fixed by a positioning pin 41 which is detachably andthreadedly fixed to the die body 11, and a supply pipe 43 which isdetachably mounted on the die body 11. The core 39 is provided at itscentral portion with a discharge hole 45 of which upper portion is incommunication with the die hole 9. The discharge hole 45 is taperedtoward its upper end.

In order to inject compressed air in a downward direction in thedischarge hole 45, a plurality of fluid injection ports 47, directeddownward of the discharge hole 45, are provided near the upper portionof the core 39. The compressed air injected from the fluid injectionport 47 may cause a rotational flow in the discharge hole 45. In orderto introduce the compressed air supplied from the supply pipe 43 to thefluid injection port 47, vertical grooves 49, extending to the uppersurface of the core 39, are formed in an outer peripheral surface of thecore 39. The core 39 is formed at its upper surface with a plurality ofcommunication grooves 51 horizontally. The communication grooves 51 arein communication with the grooves 49 and the fluid injection port 47.

According to the structure in which the communication grooves 51 formedin the upper surface and the fluid injection ports 47 are incommunication, outlets of the inclined fluid injection ports 47 can beprovided at relatively high positions, and the slug rising can beprevented more effectively.

In the above structure, if the compressed air is supplied to each groove49 through a hole 43H of each supply pipe 43 provided at pluralpositions, the compressed air is injected from the plurality of fluidinjection ports 47 provided in the core 39 downward of the dischargeholes 45, and the punching punched out in the die hole 9 is downwardlydrawn and dropped as in the previous embodiment, and the same effect asthat of the previous embodiment can be exhibited.

A lower conduit 40 of the supply pipe 43 may be formed annularly and maybe brought into communication with each groove 49 so that the pluralityof supply pipes 43 may be formed as one pipe.

Since the discharge hole 45 has the tapered hole, air flowing throughthe discharge hole 45 is faster at its upper portion than at is lowerportion, and the punching can be drawn and dropped from the die hole 9more effectively.

FIG. 3 shows a third embodiment of the die 5. This die 5 has basicallythe same structure as that shown in FIG. 1, and members having the samefunction are designated with the same symbols, and redundant explanationis omitted. In the die 5, the core 15 is provided at its upper portionwith a seal member 53 such as an O-ring to prevent compressed air fromleaking from a gap between the upper surface of the core 15 and an uppersurface of the recess 17 into which the core 15 is inserted.

Therefore, air is not leaked downward of the die hole 9, and thenegative pressure portion can effectively be generated at a lower sideof the die hole 9.

A die according to a fourth embodiment of the present invention willnext be explained with reference to the drawings.

With reference to FIG. 4, a die 101 according to the fourth embodimentof the present invention has a cylindrical die body 105 provided at itsupper portion with a die hole 103, and a discharge hole 107 having alarger diameter than that of the die hole 103. The discharge hole 107 isprovided in the die body 105. A hole-forming tool engaging section isformed on an upper portion of an outer peripheral surface of the diebody 105. The hole-forming tool engaging section engages with ahole-forming tool which forms the air injection hole 113 when the airinjection hole 113 is to be formed such that a tip end of thehole-forming tool does not slip. As one example of the hole-forming toolengaging section, the die body 105 is formed at its outer peripheralsurface with an inclined surface 109 of which side close to an axis ofthe die body 105 becomes high. In FIG. 4, the inclined surface 109 is aperipheral groove 111 having an arc (C-shaped) cross section forexample. The peripheral groove 111 may have a V-shaped cross section.The peripheral groove 111 may be formed in an outer peripheral surfaceof the die body 105 partially or over its entire circumference.

The inclined surface 109 is provided with inlets of the plurality of airinjection holes 113 in the circumferential direction at equal distancesfrom one another. Air is injected through the air injection holes 113downward of the discharge hole 107. It is desirable that the axis of theair injection hole 113 intersects with the inclined surface 109 at rightangles. To be precise, since the inclined surface 109 is illustrated tohave the arc cross section in the embodiment, it is desirable that theaxis of the air injection hole 113 intersects, at right angles, with atangent at an intersection point between the axis of the air injectionhole 113 and a curved surface of the inclined surface 109 having an arccross sectional shape. However, it is not always necessary that thetangent and the axis intersect with each other at right angles, and theymay be inclined to some extent within a permissible range.

As can be understood from the above, since the air injection hole 113 isformed at a portion of the inclined surface 109 as the hole-forming toolengaging section, a component of force generated in a tip end of thehole-forming tool engaging section when the air injection hole 113 isformed while applying thrust to the drill is small. Therefore, even whena thin and long drill is used as the hole-forming tool for making thehole, the tip end of the drill does not slip with respect to theinclined surface 109 and the tip end is engaged with the inclinedsurface 109. Thus, it is possible to prevent the drill tip end fromdeviating from the drilling position by the component of force which isapplied to the drill tip end at the time of the drilling operation.Therefore, the air injection hole 113 can easily be formed withoutdamaging the hole-forming tool such as a drill.

The peripheral groove may be of U-shape in cross section. In this case,the groove may not be provided over the entire circumference in theouter peripheral surface of the die body 105, and it is sufficient toprovide the grooves only in the necessary portions in the die body 105,but the groove may be formed over the entire circumference. Such agroove can be formed by cutting a part of the outer peripheral surfaceof the die body 105 using a milling cutter or the like.

With the structure in which the groove having the U-shaped cross sectionis formed in the outer peripheral surface of the die body 105 asdescribed above, the tip end of the hole-forming tool such as a drill ispositioned or placed on the angle portion which intersects with a planeto form the hole. With this, the tip end of the drill does not slip bythe component of force applied to the tip end of the drill and the tipend is engaged. Therefore, the inclined air injection hole 113 caneasily be formed in the die body 105.

When the air injection hole 113 is to be formed, the hole-forming toolis not limited to a cutting tool such as the drill, and the airinjection hole 113 can also be formed using electrical dischargemachining using a thin pipe material as an electrode. In this case, theelectrode functions as the hole-forming tool.

FIG. 5 show a fifth embodiment of the present invention. Constituentelements having the same function as those of the previous structure aredesignated with the same symbols, and redundant explanation is omitted.In the fifth embodiment, a plurality of portions of the outer peripheralsurface of the die body 105 are subjected to countersinking workingusing a rotating cutting tool such as an end mill, thereby forming thehole-forming tool engaging section. That is, an inclined surface 117corresponding to the inclined surface 109 is formed at a bottom of acountersunk portion 115.

In this structure, when the countersunk portion 115 is to be formed inthe outer peripheral surface of the die body 105 in a state where anaxis of a milling cutter such as the end mill is appropriately inclinedwith respect to an axis of the die body 105, the inclined surface 117 isformed flat. Therefore, the air injection hole 113 can be formed suchthat the hole intersects with the inclined surface 117 at right angles,and even if the drill is thin and long, its tip end does not slip by thecomponent of force, and the hole can be formed easily without damagingthe drill. That is, the hole can be formed in a state where the drill asa hole-forming tool is engaged without slipping at its tip end.

FIG. 6 show a sixth embodiment of the present invention. Constituentelements having the same function as those of the previous structure aredesignated with the same symbols, and redundant explanation is omitted.In the sixth embodiment, a plurality of portions of the die body 105 ofthe die 101 are formed with vertically long through holes 119. As shownin FIG. 7, a rubber or resin outer piece 123 is fitted into each of thethrough holes 119. The outer piece 123 has a previously inclined airinjection hole 121.

According to this structure, the resin outer piece 123 having the airinjection hole 121 is fitted into and fixed to the through hole 119formed in the die body 105. Therefore, the die 101 having the airinjection hole 121 can easily be created.

When the outer piece 123 is made of resin which can relatively easily beworked, it is also possible to form the air injection hole 121 after theouter piece 123 is fitted into and fixed to the through hole 119 of thedie body 105.

FIG. 8 show a seventh embodiment of the present invention. Constituentelements having the same function as those of the previous structure aredesignated with the same symbols, and redundant explanation is omitted.In the fourth embodiment, the hole-forming tool engaging section isprovided on the inner peripheral surface of the discharge hole 107 ofthe die body 105. FIG. 8A exemplifies a structure in which an innerperipheral groove 125 corresponding to the peripheral groove 111 isformed as the hole-forming tool engaging section, and the peripheralgroove 125 is formed with the air injection hole 113. FIG. 8B shows astructure in which a tapered surface 127 is formed with the airinjection hole 113 as the hole-forming tool engaging section. FIG. 8Cexemplifies a structure in which the inner peripheral surface of the diebody 105 is formed with a countersunk portion 129 which is the same asthe countersunk portion 115, the countersunk portion 129 functions asthe hole-forming tool engaging section, and the countersunk portion 129is formed with the air injection hole 113.

According to the above structures also, a component of force whichdamages the hole-forming tool is not applied when the air injection hole113 is formed, and the air injection hole 113 can easily be formed.

FIG. 9 show an eighth embodiment of the present invention. Constituentelements having the same function as those of the previous structure aredesignated with the same symbols, and redundant explanation is omitted.In the eighth embodiment, the die body 105 has a die chip 131 includingthe die hole 103. The air injection hole 113 is formed at a positionwhere the air injection hole 113 does not interfere with the die chip131.

FIG. 9A exemplifies a structure in which the tapered surface 127 isformed with the air injection hole 113 as the hole-forming tool engagingsection. FIG. 9B exemplifies a structure in which the air injection hole113 is formed in a step (angle portion) 133 of the peripheral groove asthe hole-forming tool engaging section.

According to these structures also, the hole-forming tool is not damagedby a component of force when the air injection hole 113 is formed, andthe air injection hole 113 can easily be formed. Although this structurehas the die chip 131, the air injection hole 113 can be formed withoutany problem.

FIG. 10 shows a ninth embodiment of the present invention which is apartial modification of the embodiment shown in FIG. 9A. In this ninthembodiment, a communication hole 135 is formed in an outer peripheralsurface of the die body 105, and the air injection hole 113 is connectedwith the communication hole 135.

According to this structure, a diameter of the communication hole 135can be formed larger than that of the air injection hole 113, the lengthof the air injection hole 113 can be made relatively short, and theinclining angle of the air injection hole 113 with respect to the axisof the die body 105 can be reduced. Therefore, a punched out slug in thedie hole 103 can more effectively be drawn downwardly by air injectedfrom the air injection hole 113.

FIG. 11 shows a tenth embodiment of the present invention. A die 201 hasa peripheral groove 211 and a plurality of air injection ports 213. Adie holder 207 is formed with a fluid supply passage. Air flows into theair injection ports 213 through the peripheral groove 211. A diameter ofeach of the air injection ports 213 is set smaller than that of thefluid supply passage formed in the die holder 207. Therefore, the flowrate of air flowing from the fluid supply passage formed in the dieholder 207 into the air injection ports 213 is increased, and the air isinjected from the air injection ports 213. With this, the downwarddrawing operation of the punching from the die hole 203 can be carriedout more effectively.

It is desirable that a cross-sectional area of the air injection port213 is set smaller than that of the peripheral groove 211. That is, ifthe cross-sectional area of the air injection port 213 is set smallerthan that of the peripheral groove 211, the downward drawing operationof the punching from the die hole 203 can be carried out moreeffectively.

FIG. 12 shows a partial modification of the tenth embodiment accordingto the present invention. An air injection port 313 of a die body 305 istapered toward its tip end into a nozzle shape. With this structure, theflow rate of air is increased at the tip end of the air injection port313.

FIG. 13 shows a partial modification of the tenth embodiment accordingto the present invention. Diameters of an air injection port 413 of adie body 405 are different at a tip end side and a peripheral grooveside. In this embodiment, although the air injection port 313 canmechanically be formed easier as compared with the above air injectionport 313, the same effect can be exhibited. That is, the air injectionport has two ports, i.e., an air injection port 413 having a relativelylarge diameter and an air injection port 415 having a relatively smalldiameter. Thus, by cutting and forming the hole having the differentdiameters by using two kinds of drills, the air injection ports 413 and415 can be formed.

FIG. 14 shows the die holder 7 of a die apparatus of an eleventhembodiment according to the present invention as viewed from its bottom.This embodiment is a partial modification of the fluid supply passage 36of the die holder 7 shown in FIG. 1. Two fluid supply holes 581 and 581are formed at opposite ends of the fluid supply hole 35. The fluidsupply holes 581 and 581 are formed with grooves 575 and 575 whichextend to positions of the dies and bend from these positions. Thesegrooves 575 and 575 are tightly connected with an upper surface of thedie base 3, thereby forming a conduit. Air flows to fluid supplypassages 583 and 583 formed in the die holder 7, and the air flows intothe peripheral groove formed in the die.

The disclosures of Japanese Patent Application Nos. 2002-177211 (filedon Jun. 18, 2002), and 2003-142267 (filed on May 20, 2003) areincorporated by reference herein in their entirety.

The embodiments of the present invention disclosed above are to beconsidered not restrictive, changes can be appropriately made, and theinvention may be embodied in other specific forms.

1. A die, comprising: a die body including a die hole configured topunch a work, the die body being configured to be inserted into a diemounting hole; and a core provided within the die body, the corecomprising a discharge hole which is in communication with the die hole,wherein the core is provided with a plurality of fluid injection portsconfigured to obliquely inject fluid downwardly of the discharge hole,and the die body is provided with an inflow port through whichcompressed fluid flows into the fluid injection ports, wherein theinflow port is positioned above an outlet of the fluid injection portswith respect to a vertically extending direction of the die body, andwherein a longitudinally extending outer surface of the core abuts alongitudinally extending inner surface of the die body.
 2. The dieaccording to claim 1, wherein the core comprises a resin, and thedischarge hole is tapered toward its upper side.
 3. The die according toclaim 1, wherein an outer peripheral surface of the die body is formedwith a peripheral groove which is in communication with the inflow port.4. A die apparatus, comprising: a die body comprising a die holeconfigured to punch a work; and a die holder formed with a die mountinghole configured to detachably hold the die body, wherein the die body isprovided with a negative pressure generator which draws a punchingpunched out by the die hole, the die body is provided with an inflowport through which compressed fluid flows into the negative pressuregenerator, the die mounting hole is provided with a seal member at anupper portion and a lower portion which prevents the compressed fluidfrom leaking, wherein the seal member is positioned within a recesssurrounding the upper and the lower portion of the die mounting hole,and the die holder is provided with a fluid supply hole through whichthe compressed fluid is supplied to the inflow port, and wherein alongitudinally extending outer surface of a core provided within the diebody abuts a longitudinally extending inner surface of the die body. 5.A die, comprising: a die body provided at an upper portion with a diehole; a discharge hole formed in the die body, the discharge holecomprising a diameter larger than a diameter of the die hole; aninclined surface formed at an outer peripheral surface of the die body;an inclined air injection hole, wherein an upper end of the inclined airinjection hole opens in the inclined surface and a lower end of theinclined air injection hole opens into a lower portion of the dischargehole so as to inject air downwardly in the discharge hole; and an inflowport configured to introduce compressed fluid into the inclined airinjection hole, wherein the inflow port is positioned above an outlet ofthe air injection hole with respect to a vertically extending directionof the die body, and wherein the inclined air injection hole is inclinedso that an axis of the inclined air injection hole intersects theinclined surface at substantially a right angle, and wherein alongitudinally extending outer surface of a core provided within the diebody abuts a longitudinally extending inner surface of the die body. 6.The die according to claim 5, further comprising: a peripheral grooveformed in an outer peripheral surface of the die body.
 7. The dieaccording to claim 5, wherein the inclined surface is formed on an outerperipheral surface of the die body by countersinking processing.
 8. Adie, comprising: a die body provided at an upper portion with a diehole; and a discharge hole formed in the die body, the discharge holecomprising a diameter larger than a diameter of the die hole, whereinthe die body is formed with a through hole which is in communicationwith the discharge hole and an outer piece is fitted into the throughhole, and the outer piece is formed with an inclined air injection holeconfigured to inject air downwardly of the discharge hole, wherein aninflow port, configured to introduce compressed fluid into the inclinedair injection hole, is positioned above an outlet of the air injectionhole with respect to a vertically extending direction of the die body,and wherein a longitudinally extending outer surface of a core providedwithin the die body abuts a longitudinally extending inner surface ofthe die body.
 9. A die, comprising: a die body provided at an upperportion with a die hole; and a discharge hole formed in the die body,the discharge hole comprising a diameter larger than a diameter of thedie hole, wherein an inner peripheral surface of the die body isprovided with a hole-forming tool engaging section, and the hole-formingtool engaging section is formed with an inclined air injection holeconfigured to inject air downwardly of the discharge hole, wherein aninflow port, configured to introduce compressed fluid into the inclinedair injection hole, is positioned above an outlet of the air injectionhole with respect to a vertically extending direction of the die body,and wherein a longitudinally extending outer surface of a core providedwithin the die body abuts a longitudinally extending inner surface ofthe die body.
 10. The die according to claim 9, wherein the hole-formingtool engaging section is a portion of an inner peripheral groove formedin an inner peripheral surface of the die body, or a countersunkportion, or a tapered surface.
 11. The die according to claim 9, whereinthe air injection hole is connected to a communication hole formed froman outer peripheral surface of the die body.
 12. A die, comprising: adie body provided at an upper portion with a die hole configured topunch a work, a lower portion of the die body being formed with adischarge hole which is in communication with the die hole, the die bodybeing configured to be inserted into a die mounting hole; an annularperipheral groove provided around an outer periphery of the die body;and a plurality of fluid injection ports provided in the die body, thefluid injection ports being inclined to obliquely inject fluiddownwardly of the discharge hole, wherein each of the fluid injectionports comprises a conduit which passes through the peripheral groove tothe discharge hole, a cross-sectional area of the fluid injection portsbeing smaller than a cross-sectional area of the annular peripheralgroove, and the die mounting hole being provided with a seal member atits upper portion and its lower portion that prevents the fluid fromleaking, wherein the seal member is positioned within a recesssurrounding the upper and the lower portion of the die mounting hole,and wherein a longitudinally extending outer surface of a core providedwithin the die body abuts a longitudinally extending inner surface ofthe die body.
 13. A die apparatus, comprising: a die body provided at anupper portion with a die hole configured to punch a work, a lowerportion of the die body being formed with a discharge hole which is incommunication with the die hole; a die holder formed with a die mountinghole configured to detachably hold the die body; a fluid supply holeformed in the die holder and configured to supply compressed fluidtoward the die body; and a plurality of fluid injection ports providedin the die body, the fluid injection ports obliquely injectingcompressed fluid supplied from the fluid supply hole downwardly of thedischarge hole, wherein a cross-sectional area of the fluid injectionports is smaller than a cross-sectional area of the fluid supply holeformed in the die holder, and the die mounting hole being provided witha seal member at its upper portion and its lower portion that preventsthe compressed fluid from leaking, wherein the seal member is positionedwithin a recess surrounding the upper and the lower portion of the diemounting hole, and wherein a longitudinally extending outer surface of acore provided within the die body abuts a longitudinally extending innersurface of the die body.
 14. A die, comprising: a die body including adie hole configured to punch a work, the die body being configured to beinserted into a die mounting hole; and a core provided in the die body,the core comprising a discharge hole which is in communication with thedie hole, wherein the core is provided with a plurality of fluidinjection ports configured to obliquely inject fluid downwardly of thedischarge hole, the die body is provided with an inflow port throughwhich compressed fluid flows into the fluid injection ports, across-sectional area of the fluid injection ports being smaller than across-sectional area of the inflow port provided in the die body, andthe die mounting hole being provided with a seal member at its upperportion and its lower portion that prevents the compressed fluid fromleaking wherein, the seal member is positioned within a recesssurrounding the upper and the lower portion of the die mounting hole,and wherein a longitudinally extending outer surface of the core abuts alongitudinally extending inner surface of the die body.
 15. A die,comprising: a die body provided at an upper portion with a die holeconfigured to punch a work, a lower portion of the die body being formedwith a discharge hole which is in communication with the die hole, thedie body being configured to be inserted into a die mounting hole; and aplurality of fluid injection ports provided in the die body, theplurality of fluid injection ports inclining to obliquely injectcompressed fluid supplied toward the die body downward of the dischargehole, wherein a cross-sectional area of the fluid injection ports issmaller than a cross-sectional area of a fluid supply port, and the diemounting hole being provided with a seal member at its upper portion andits lower portion that prevents the compressed fluid from leakingwherein, the seal member is positioned within a recess surrounding theupper and the lower portion of the die mounting hole, and wherein alongitudinally extending outer surface of a core provided within the diebody abuts a longitudinally extending inner surface of the die body. 16.A die, comprising: a die body provided at an upper portion with a diehole configured to punch a work, a lower portion of the die body beingformed with a discharge hole which is in communication with the diehole, the die body being configured to be inserted into a die mountinghole; and a plurality of fluid injection ports provided in the die body,the plurality of fluid injection ports being inclined to obliquelyinject compressed fluid supplied toward the die body downwardly of thedischarge hole, wherein a cross-sectional area of the fluid injectionports is smaller than a cross-sectional area of a fluid supply portformed in the die holder which detachably holds the die body, in orderto supply the compressed fluid toward the die body, and the die mountinghole being provided with a seal member at its upper portion and itslower portion that prevents the compressed fluid from leaking, whereinthe seal member is positioned within a recess surrounding the upper andthe lower portion of the die mounting hole, and wherein a longitudinallyextending outer surface of a core provided within the die body abuts alongitudinally extending inner surface of the die body.